Use Ruby programming for the following:

An int-array is an array of zero or more int-expressions, where an int-expression is an integer or an int-array. Informally, an int-array is an array of integers that can nest to any depth. Write a function count_occurrences_rec(a, i) that counts the number of times that the integer i occurs in the int-array a.

>> a

=> [1, [1, 2], [[[1, 1], 1]]]

>> count_occurrences_rec(a, 1)

5

>> count_occurrences_rec(a, 2)

1

>> count_occurrences_rec(a, 3)

0